On recommendations from members of this community, my interest in tubes has been piqued. I only have experience with solid state gear, so I don’t necessarily know how to best start exploring the tube world. Amazon has a bunch of inexpensive tube preamps like this:
Nobsound HiFi 6J1 Vacuum Tube Preamplifier Stereo PreAmp Digital Treble&Bass Tone Control (Black) https://www.amazon.com/dp/B01NBM7K8L/ref=cm_sw_r_cp_apa_i_NhPhDbJEMJ5HE
Any thoughts on whether putting one of those between a DAC and a solid state amp - either headphone amp or speaker amp - would be a good enough starting point to see if I even like what tubes bring to the table? Or should I be looking elsewhere entirely? Budget is limited and I’m very much in the early ‘is this worth exploring further?’ phase. Thanks to all in advance!
I’d say spend a bit more and get yourself the Schiit Vali 2 or Valhalla 2…I want the Valhalla 2 myself. 
I only have experience with the schiit preamps like the saga and the freya… they both sound amazing with speaker systems… if its a headphone amp you want a “tube” experience… then the Darkvoice is your best bet…I wouldn’t add another line in the chain when it comes to headphones it usually muddy’s things up… I tried to use the freya to inject tubes into my headphones… kind of a bad idea.
Dedicate to one or the other… you can use the dark as a pre…I don’t however… and there are plenty of threads dedicated to rolling tubes for the darkvoice…
AS is on the money there…Zeos loves his Darkvoice, but also had very good things to say about the Vali 2 and Valhalla 2 as well. and Schiit is a very safe, if not uninspiring, stack of equipment to go for.
I have used the Schiit Modi 3/Magni 3 stack for a few months and agree with your Schiit opinion. Plus, anyone who has the stones to use a middle school-level profanity and toilet humor pun as their company name deserves our financial support, IMHO 
I see the Vali is only $149. Definitely considering it, but also eager to hear other opinions before making a decision.
I’d be more interested in checking over multiple reviews on the tube amps rather than opinions…cause just like assholes, everyone has one! 
I can confirm that Vali 2 does sound different from solid state amps. Whether that is “tubey” or not, I can’t say.